a) Field of the Invention
The present invention broadly relates to an apparatus for modulating the intensity of an X-ray beam generated in a given direction by an X-ray tube.
More specifically, the invention relates to an apparatus of the above mentioned type, hereinafter called "X-ray beam modulator", that is motorized, remotely controlled and easy to operate, thereby making it easy to use into the X-ray cone and tube assembly of a radiographic system, such as, for example, a system for lower limb angiography, in order to obtain better density and contrast and less radiation exposure of the patient's legs and feet.
b) Brief Description of the Prior Art
It is well known that the X-ray absorption of a body depends on the thickness and/or density of this body. Thus, in a human being, the X-ray absorption varies substantially according to both the portion of the anatomy to be radiographed, and the specific body feature of the patient who is radiographed, depending on the thickness of his or her bones and his or her weight.
Accordingly, there is a need for an apparatus for modulating the intensity of the X-ray beam projected towards a patient, depending on the portion of his or her anatomy to be radiographed and his or her physical condition, in order to achieve proper density and contrast over the entire radiographic film without unduly overexposing some portion of the patient's body.
So far, such a need has been fulfilled with filters of different absorption rates that must be selected and positioned to intersect the X-ray beam according to the radiographic need. Such filters are of course very efficient, but time consuming to install.